U.S. patent application number 11/411945 was filed with the patent office on 2007-11-01 for color organic light emmitting diode display.
This patent application is currently assigned to Wintek Corporation. Invention is credited to Chien-Chung Kuo, Wei-Shan Ma.
Application Number | 20070252514 11/411945 |
Document ID | / |
Family ID | 38647695 |
Filed Date | 2007-11-01 |
United States Patent
Application |
20070252514 |
Kind Code |
A1 |
Kuo; Chien-Chung ; et
al. |
November 1, 2007 |
Color organic light emmitting diode display
Abstract
A simple and inexpensive structure of color organic light
emitting diode display includes a transparent substrate, a color
filter layer, a first electrode layer, an organic layer and a
second electrode layer arranged orderly one by one. The color
filter layer, which is disposed between the substrate and the first
electrode layer, has a plurality of conductive first line members
respectively electrically connected to the electrodes of the first
electrode layer for use as auxiliary electrodes to reduce
resistance of the circuit layout while maintaining aperture ratio
of the pixel.
Inventors: |
Kuo; Chien-Chung; (Taichung
County, TW) ; Ma; Wei-Shan; (Taichung County,
TW) |
Correspondence
Address: |
BACON & THOMAS, PLLC
625 SLATERS LANE
FOURTH FLOOR
ALEXANDRIA
VA
22314
US
|
Assignee: |
Wintek Corporation
TAICHUNG
TW
|
Family ID: |
38647695 |
Appl. No.: |
11/411945 |
Filed: |
April 27, 2006 |
Current U.S.
Class: |
313/504 |
Current CPC
Class: |
H01L 51/5212 20130101;
H01L 27/322 20130101 |
Class at
Publication: |
313/504 |
International
Class: |
H01J 1/62 20060101
H01J001/62; H01J 63/04 20060101 H01J063/04 |
Claims
1. A color organic light emitting diode display comprising: a
transparent substrate; a color filter layer disposed on the
transparent substrate, the color filter layer comprising a
plurality of first line members, a plurality of second line members
and a filter matrix, the first line members being electrically
conductive and light-blocking, the second line members being
respectively arranged between each two adjacent first line members,
the filter matrix comprising a plurality of color films arranged in
spaces surrounded by the first line members and the second line
members; a first electrode layer arranged above the color filter
layer, the first electrode layer comprising a plurality of
transparent electrodes isolated from one another and respectively
electrically connected to the first line members; an organic layer
arranged above the first electrode layer for emitting white light;
and a second electrode layer disposed on the organic layer.
2. The color organic light emitting diode display as claimed in
claim 1, further comprising an insulative layer disposed between
the color filter layer and the first electrode layer, the
insulative layer comprising a plurality of transparent insulative
films and a plurality of first crevices between each two
transparent insulative films; the transparent electrodes of the
first electrode layer being respectively arranged on the insulative
films and each having an extension rib respectively extending to
the first crevices and respectively connected to the first line
members.
3. The color organic light emitting diode display as claimed in
claim 1, further comprising an insulative layer disposed between
the color filter layer and the first electrode layer, and a
plurality of conductive ribs, the insulation layer comprising a
plurality of transparent insulative films and a plurality of second
crevices respectively defined between each two adjacent transparent
insulative films, the conductive ribs being respectively formed in
the first crevices and each having a first end respectively
connected to the first line members and a second end respectively
connected to the transparent electrodes of the first electrode
layer.
4. The color organic light emitting diode display as claimed in
claim 2, wherein the insulative layer is made of photosensitive
acrylic resin.
5. The color organic light emitting diode display as claimed in
claim 3, wherein the insulative layer is made of photosensitive
acrylic resin.
6. The color organic light emitting diode display as claimed in
claim 1, wherein the first electrode layer further comprises a
plurality of second crevices defined between each two adjacent
transparent electrodes, and the color organic light emitting diode
display further comprises a plurality of separation films
respectively formed in the second crevices.
7. The color organic light emitting diode display as claimed in
claim 1, wherein the first line members each comprise a metal layer
for the connection of the transparent electrodes of the first
electrode layer respectively.
8. The color organic light emitting diode display as claimed in
claim 7, wherein the first line members each further comprise a
compound layer supporting the respective metal layer.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a color display, and more
particularly, to a color organic light emitting diode display.
[0003] 2. Description of the Related Art
[0004] Basically, there are three conventional techniques to
achieve a color organic light emitting diode display, i.e.,
side-by-side separate RGB emitting subpixels, color change medium
(CCM) and white organic light emitting diode (OLED) integrated
color filter technique. Among these three techniques, white OLED
integrated color filter technique, which applies an organic layer
for generating white light with a color filter, is the mostly
popularly accepted technique for the advantages of easy
manufacturing and high yield rate.
[0005] FIG. 4 shows a color organic light emitting diode display 3
made according to the white OLED integrated color filter technique.
The color organic light emitting diode display 3 comprises from the
bottom toward the top thereof a substrate 80, a color filter layer
81, an overcoat layer 82, a plurality of first electrodes 83, a
plurality of insulators 84 arranged in parallel between the first
electrodes 83, a plurality of metal conductive members 85
respectively disposed corresponding to the upper fringe of the
first electrodes 83, an organic layer 86 capable of generating
white light, and a plurality of second electrodes 87 arranged
perpendicularly relative to the first electrodes 83. The color
filter layer 81 is comprised of a plurality of partition films 81a
that are intersected with one another thereby forming a black
matrix (BM) that can block light and has a plurality of
predetermination spaces, and a plurality of color films 81b
respectively formed in the predetermination spaces. These color
films 81b are made of photoresists of red (R), green (G) or blue
(B) colors respectively. Each color film 81b forms a sub-pixel of
the display 3. A pixel zone comprises three different color films
81b, R, G and B. By means of driving the organic layer 86 to emit
white light through the color filter layer 81, the display 3
provides an image of full color.
[0006] Since the first electrodes 83 need to be transparent
conductive films that have a high resistance, they are not suitable
for use directly as a conductive circuit for driving the
above-mentioned display 3. Therefore, the aforesaid metal
conductive members 85 electrically respectively connected to the
first electrodes 83 are used as auxiliary electrodes. When a data
signal is simultaneously transferred to the first electrode 83
through a corresponding metal conductive member 85, and a scan
signal to is transferred to the second electrode 87,
predetermination spaces of the organic layer 86 will emit white
light that passes through the corresponding color film 81b to
further produce a color image. Metal materials and many other
conductive compound materials (such as silver, silver alloy,
aluminum, aluminum alloy, and etc.) may be selectively used for
making the aforesaid auxiliary electrodes. Auxiliary electrodes
made of metal materials have low resistance, however they are
opaque. Therefore, the metal conductive members 85 block a part of
the white light that emits from the organic layer 86 to the color
films 81b. Consequently, the effective light emitting area is
reduced and the aperture ratio of pixel is decreased. When reducing
the area of the auxiliary electrodes in order to maintain the
aperture ratio of pixel, the conductivity will be relatively
lowered, resulting in a relative increase of the resistance of the
circuit layout. When increasing the thickness of the auxiliary
electrodes in order to improve the problems of aperture ratio and
impedance, the manufacturing process will be complicated, resulting
in a high manufacturing cost.
SUMMARY OF THE INVENTION
[0007] The present invention has been accomplished under the
circumstances in view. It is therefore the main object of the
present invention to provide a color organic light emitting diode
display, which provides a full-color image output, eliminates the
impedance problem of circuit layout, and increases the aperture
ratio.
[0008] It is another object of the present invention to provide a
color organic light emitting diode display, which reduces the
design of auxiliary electrodes, thereby shortening the
manufacturing process, improving the yield rate and lowering the
manufacturing cost.
[0009] To achieve these objects of the present invention, the color
organic light emitting diode display comprises a transparent
substrate, a color filter layer formed on the transparent
substrate, and a first electrode layer formed above the color
filter layer. The color filter layer has a plurality of first line
members, a plurality of second line members and a filter matrix.
The first line members are electrically conductive and
light-blocking. The second line members are respectively arranged
between each two adjacent first line members. The filter matrix has
a plurality of color films arranged in spaces surrounded by the
first line members and the second line members. The first electrode
layer comprises a plurality of transparent electrodes isolated from
one another and respectively electrically connected to the first
line members. In a preferred embodiment of the present invention,
the color organic light emitting diode display further comprises an
organic layer arranged above the first electrode layer for emitting
white light, and a second electrode layer arranged above the
organic layer and provided with a plurality of electrodes extending
along a direction perpendicular to the extending direction of the
electrodes of the first electrode layer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a schematic exploded view of a color organic light
emitting diode display according to a first preferred embodiment of
the present invention.
[0011] FIG. 2 is a sectional assembly view of the color organic
light emitting diode display according to the first preferred
embodiment of the present invention.
[0012] FIG. 3 is a sectional assembly view of the color organic
light emitting diode display according to a second preferred
embodiment of the present invention.
[0013] FIG. 4 is a schematic sectional view of a color organic
light emitting diode display according to the prior art.
DETAILED DESCRIPTION OF THE INVENTION
[0014] Referring to FIGS. 1 and 2, a color organic light emitting
diode display 1 in accordance with the first preferred embodiment
of the present invention is shown comprising a transparent
substrate 10, a color filter layer 20, an insulative layer 30, and
an OLED (organic light emitting diode) 40.
[0015] The transparent substrate 10 has a top surface 101 and a
bottom surface 102. Because the substrate 10 is set at the bottom
side of the color organic light emitting diode display 1 and
optical signal passes out of the bottom surface 102 of the
transparent substrate 10, the color organic light emitting diode
display 1 in the present preferred embodiment is a bottom-emitting
type display. Because the substrate 10 must have the characteristic
of fully transparent for free passing of optical signal, a
transparent material is used for making the substrate 10. Further,
the top surface 101 of the substrate 10 is well polished to prevent
dispersion of light that may result in attenuation of light and
other optical interference.
[0016] The color filter layer 20 is covered on the top surface 101
of the transparent substrate 10, comprising a plurality of first
line members 21, a plurality of second line members 22, and a color
filter matrix 23.
[0017] The fabrication of the first line members 21 and the second
line members 22 are described hereinafter.
[0018] Because the color organic light emitting diode display 1 is
a bottom-emitting type display, a light absorptive chrome oxide
film is coated on the substrate 10 at first to prevent interference
of reflective light upon radiation of external light source onto
the bottom surface 102, and then a chrome is coated on the chrome
oxide film for the advantage of good conductivity, and then using
photolithography technology to form a pattern on the substrate 10
that contains the first line members 21 and second line members 22.
The first line members 21 extend in longitudinal direction. The
second line members 22 are respectively transversely arranged
between each two adjacent first line members 21. The first line
members 21 and the second line members 22 each have a laminated
structure comprised of a compound layer 201 of chrome oxide and a
metal layer 202 of chrome as shown in FIG. 2. The metal layer 202
has light-blocking and electrically conductive characteristics.
Each second line member 22 has one end connecting one first line
member 21 and the other end spaced from another first line member
21 at a distance. This arrangement prevents a short circuit between
the first line members 21 by the second line members 22 upon input
of electric drive signal. During fabrication of the first line
members 21 and the second line members 22, the compound layer 201
may be eliminated while maintaining the metal layer 202 fabrication
process. This method has the first line members 21 and the second
line members 22 made of a single layer structure with good
conductivity.
[0019] The filter matrix 23 is made as follows.
[0020] After formation of the first line members 21 and the second
line members 22, red, green and blue photoresists are respectively
orderly formed in the spaced surrounded by the first line members
21 and the second line members 23, thereby forming color films 231,
232, 233. These color films 231, 232, 233 form the color filter
matrix 23. At this time, the fabrication of the color filter layer
20 is completed.
[0021] Because repeating a forming process several times makes the
filter matrix 23 of the color filter layer 20, in order to have a
flat interface for the attachment of the later OLED 40 the
insulative layer 30 is used in the present embodiment to be covered
on the topside of the color filter layer 20. The insulative layer
30 is formed on the color filter layer 20 from photosensitive
acrylic resin and then processed the patterning process, thereby
forming multiple strips of transparent insulative film 31 and a
crevice 32 between each two strips of transparent insulative film
31. The strips of transparent insulative films 31 are arranged in
parallel to the first line members 21 and respective covered on the
color films 231, 232, 233, as shown in FIG. 2. These first crevices
32 correspond to the first line members 21, allowing exposure of
the first line members 21 partially. These strips of transparent
insulative film 31 allow the light of the OLED 40 to pass
completely, protect the color films 231, 232, 233 against
interference of high temperature during the posterior manufacturing
procedures, and provide a good adhesion between the color filter
layer 20 and the OLED 40.
[0022] The OLED 40 comprises a first electrode layer 41, a
plurality of separation films 42, an organic layer 43, and a second
electrode layer 44. The first electrode layer 41 is comprised of a
plurality of transparent electrodes 411 and a plurality of
extension ribs 412. The first electrode layer 41 is made by
depositing a thin layer of ITO (INDIUM TIN OXIDE) on the top
surface of the insulative layer 30 and then using photolithography
technology to pattern the ITO film into multiple strips of
transparent film, i.e., the aforesaid transparent electrodes 411.
At this time, a second crevice 413 is formed between each two
adjacent transparent electrodes 411, and a part of the ITO film
that fills the first crevices 32 is maintained after
photolithographic process and forms the aforesaid extension ribs
412. These extension ribs 412 each have one end respectively
electrically connected to the first line members 21, i.e., the
electrodes 411 and the first line members 21 are directly connected
together so that the first line members 21 are used as signal lines
for driving the color organic light emitting diode display 1.
[0023] The separation films 42 are strip members formed by coating
photosensitive polyimide on the first electrode layer 41 and
patterning the photosensitive polyimide coating into strips that
fill up the second crevices 413 and arranged in parallel to the
first line members 21, as shown in FIG. 2. Each separation film 42
covers the border areas of the two adjacent transparent electrodes
411 to isolate the transverse electric field effect between two
adjacent transparent electrodes 411 so as to prevent optical
interference due to interference of margin electric field effect
upon light emission of the OLED 40.
[0024] Covering a layer of organic light emitting diode material on
the first electrode layer 41 and the separation films 42 forms the
organic layer 43. Thereafter, a conductive material (for example,
aluminum) is deposited on the organic layer 43 and patterned into
strip-like electrodes 441. These electrodes 441 form the aforesaid
second electrode layer 44. Further, these electrodes 441 are
arranged at right angles relative to the transparent electrodes
411. The second electrode layer 44 works as signal line means for
driving the color organic light emitting diode display 1.
[0025] Further, in addition to the strip-like structure that fills
up the second crevices 413 and arranged in parallel to the first
line members 21 when making the separation films 42, an additional
grid-like insulation film may be formed corresponding to the second
line members 22 and arranged at right angles relative to the
strip-like structure for use isolation means to prevent electric
connection between each two electrodes 441 of the second electrode
layer 44, so as to reduce the transverse electric field effect
between each two adjacent electrodes 441 and to improve the quality
of the OLED 40.
[0026] According to the present invention, the light-blocking first
line members 21 and the second line members 22 that separate the
color films 231, 232, 233 are made electrically conductive, and the
electrodes 411 of the first electrode layer 41 are directly and
electrically connected to the first line members 21 for enabling
the first line members 21 to work as auxiliary electrodes for the
electrodes 411 of the first electrode layer 41. Therefore, the
invention has a low resistance characteristic while maintaining the
optimum aperture ratio, i.e., the invention eliminates the problem
that high aperture ratio and low resistance cannot exist at the
same time in the prior art designs. Further, the invention shortens
the fabrication of the auxiliary electrodes, thereby improving the
yield rate and lowering the manufacturing cost.
[0027] FIG. 3 shows a second preferred embodiment of the present
invention. According to this embodiment, the color organic light
emitting diode display 2 is substantially similar to the aforesaid
first embodiment in structure with the exceptions outlined
hereinafter.
[0028] After formation of the insulative films 31 and the first
crevices 32 during fabrication of the color organic light emitting
diode display 2, conductive ribs 50 are formed in the first
crevices 32, keeping one end of each conductive rib 50 in contact
with the first line members 21 respectively. Thereafter, the first
electrode layer 41 is formed and the electrodes 411 of the first
electrode layer 41 touch the other end of each of the conductive
ribs 50 respectively. Thus, the first line members 21 and the
electrodes 411 are electrically connected, and the first line
members 21 work as auxiliary electrodes for the electrodes 411 of
the first electrode layer 41. Therefore, this alternate form has
the characteristic of low resistance while maintaining the aperture
ratio.
[0029] Although particular embodiments of the invention have been
described in detail for purposes of illustration, various
modifications and enhancements may be made without departing from
the spirit and scope of the invention. Accordingly, the invention
is not to be limited except as by the appended claims.
* * * * *